The present invention pertains to a method and related apparatus for reloading a conventional pipette tip holder with an array of replacement pipette tips and, more particularly, to a system in which the replacement pipette tips are loaded into the holder without interposing any transfer device between the holder and the tips.
In biochemical, pharmaceutical and clinic testing, pipetting apparatus is used to transfer small volumes of reagents and samples for various types of testing and assay procedures. Pipette tips are conventionally furnished in tip holders which carry 96 pipette tips in a rectilinear 8×12 array. The tip holder includes a flat support surface provided with an array of openings for the pipette tips which are supported fairly loosely therein so they may be easily picked up with the probe tip of a pipettor device. Furthermore, pipettors may be adapted to pick up a single tip or multiple tips at one time, typically multiple tip pipettors will pick up eight or twelve tips (comprising an entire row in a tip holder) at one time.
A pipette tip holder also typically comprises an enclosing box having a removable cover. The flat tip support surface carrying an array of tips generally lies over the top of the box with the lower tapered tip ends extending downwardly into the box and the upper ends of the tips, comprising mounting collars for receipt of the pipettor probes, extending upwardly from the support surface and enclosed by the lid. It has long been recognized that there are economies in reloading a pipette holder with replacement tips once it has been emptied, instead of discarding the entire tip holder box. It has also been long recognized that reloading an empty pipette tip holder required apparatus and methods that would permit the transfer of an entire array of 96 tips in order to make reloading practical. The reloading apparatus is usually less expensive than the original tip holder, but it should also be simple to use, be capable of packaging to facilitate shipment and storage, and minimize the amount of scrap.
A number of prior art reloading systems have been developed with the intent of addressing the foregoing requirements. Several of these systems utilize a simple carrier or transfer plate in which an array of 96 pipette tips is carried to and placed on the support surface of an empty tip holder, whereafter the pipettor may connect to and withdraw a tip or tips in the usual way. However, such prior art tip transfer devices are either unduly complex or do not provide sufficient stability and alignment for the replacement array of tips so that they may be easily inserted into the openings in the original pipette holder without undue adjustment and maneuvering. Furthermore, because conventional pipette tip holders are often utilized with mechanical or robotic pipettor devices that are adjusted or programmed to move to and from fixed pipette tip locations, reloading systems which place a transfer plate or card filled with replacement tips onto the pipette holder change the locations of the upper ends of the pipette tips (progressively raising the positions with each replacement array), so that they may interfere with the operation of a mechanical or robotic pipettor.
The subject invention addresses all of the requirements of a pipette tip replacement or reloading system but, in addition, does so without placing and leaving any transfer plate or other device on the tip holder between the holder support surface and the replacement pipette tips.